The need for separation of hydrocarbons, e.g. oil or bitumen, from mineral deposits with which they are found naturally associated, sands and shales, becomes more acute as conventional petroleum resources become depleted. Tar sand formations contain large reserves of hydrocarbons, which can only be exploited if an economical, commercial method of separating the bitumen from the sand is developed. Similarly, secondary oil recovery to extract residual oil from oil bearing formations from which primary, self-energized oil extraction by conventional drilling has been completed, requires an economical separation method.
In the treatment of hydrocarbon bearing mineral deposits such as tar sands, oil shales and other oil-bearing mineral formations, it is possible to effect substantial separation of the hydrocarbon values from the inorganic mineral constituents by washing with cold water containing a synthetic chemical surfactant as extraction aid. This shows promise as a commercially acceptable extraction process in many instances. It avoids the high energy costs associated with the alternative hot water wash processes and steam-drive processes. It also leads to cleaner separations, since it does not alter the surface properties of the clay residue and complicate the settling thereof from the resultant aqueous suspensions, as the hot water processes tend to do. It is however necessary to use a low cost non-toxic, biodegradable and separation-effective surfactant if the cold water process is to be commercially and environmentally attractive.
The production of surface active substances by microbes is well-known. Microbially produced surfactants have chemical structures and properties which are considerably different from those of known, synthetic surfactants. By their very nature, microbially produced surfactants are biodegradable. They also have the potential for cheap production. Some microbially produced surfactants have been reported to have emulsification properties.